Calculation of Tyre Noise Radiation with a Mixed Approach

The radiation of tyre noise is computed using a hybrid integral/ beam tracing approach called GRIM. It is simply an integral over the vibrating tyre, of the product of the known velocity by the full Green function which takes into account all the multiple reflections and diffraction between tyre, ground and car body. This Green function can be calculated by means of a beam tracing program named ICARE – which can deal with curved surfaces and multiple diffraction. This approach makes the link between tyre models and reception points well outside the car. In order to deal with small scale phenomena, close to contact, a combined use of BEM and beam tracing is showed to bypass the limitations of both geometrical and BEM approaches.